I'm pleased to announce the availability of a new white paper that I have authored on the topic of environmental control of cannabis grow rooms. Since many engineering firms are being asked to design a grow facility for the first time, it is my hope that this white paper will provide a good basis for understanding the unique challenges of the cannabis industry and how they can be addressed with the right equipment.

For some time now, I have been working directly with some of the premier grow facilities in the United States, and this white paper outlines a great deal of what I have learned. I hope you find it informative.

Here is an excerpt from "Precision Environmental Controls for the Medical Cannabis Industry":

In October of 2016, Peter Judge writing for Data Center Dynamics asked the question “Why not diversify into dope?” The byline was meant to have shock value and thus the choice of words. Most folks today would use the word cannabis as opposed to some of the more colorful terms used for this particular plant. In his article Mr. Judge cited several similarities between the requirements for the environmental controls for data centers and those for cannabis grow facilities. He asked the important question: “Energy demand is high, and indoor cannabis farms also need cooling. Do we have the expertise to help?” He even cited some of the work that we here at STULZ USA have done in this growing industry.

As of this writing, 29 states and the District of Columbia have some form of legal cannabis, be it medical, recreational, or both. Medical cannabis has achieved wide acceptance in the medical community as a legitimate course of treatment for illnesses such as glaucoma, childhood seizures, bipolar disorder, schizophrenia, weight loss during chemotherapy, and many others. Cannabis is still federally prohibited as a Schedule I drug, and while it is unclear how the current administration will address recreational use, it has signaled that it will not interfere with the medical side of the industry in states where cannabis has been made legal via referendum.

The US government has stipulated that it shall receive all tax revenues it is owed from the sale of state legal cannabis and it has eased banking laws to shift the industry away from a cash-only to a more traditional commerce model. Though the government could change its stance on cannabis at any time (simply by enforcing current federal laws), the scale of the continued investment seems to indicate that the market place believes it will not.

How does this affect us as a producer and seller of precision HVAC products? Clearly it presents us with opportunities that were not there just a few years ago. The environmental control of the grow facility is very similar to that of the data center with one glaring exception. The grow room has a large latent load not present in a typical data center application. This latent load comes from the large amounts of water that are fed to the plants on a daily basis. This water, which is removed primarily by the HVAC system, is produced through a biological mechanism known as “transpiration” (more on that later). To understand the latent load we need to understand a little about how the plant behaves at different times in its life cycle.

The primary heat load is generated by high intensity grow lights. The type of lighting, and the lighting sequence used to manipulate the plants’ life cycle, dictates the amount of load in the space. The types of lights primarily used in this industry include high-pressure sodium lights (higher energy usage, higher plant grow rate) and LED lights (lower energy usage, lower plant grow rate). In the modern indoor grow facility we typically see smaller rooms, internal to a larger facility, where the plants are protected, conditioned, and manipulated as they go through their grow cycle such that they produce the greatest yield in the shortest period of time. The environmental conditions around the grow pods are kept close to grow room conditions to minimize the impact of infiltration and exfiltration on the heat and moisture load in the grow space.

How does this affect us as a producer and seller of precision HVAC products? Clearly it presents us with opportunities that were not there just a few years ago. The environmental control of the grow facility is very similar to that of the data center with one glaring exception...

Dave Meadows is the Director of Industry, Standards and Technology at STULZ USA. He has a BS in Mechanical Engineering from the University of Maryland, Baltimore County, and is an active participant on ASHRAE committees.